Drop-on-demand ink jet printing systems eject ink drops from printhead nozzles in response to pressure pulses generated within the printhead by either piezoelectric devices or thermal transducers, such as resistors. The ejected ink drops, commonly referred to as pixels, are propelled towards an image receiving member where the ink drops form spots on the member. The printheads have drop ejecting nozzles and a plurality of ink containing channels, usually one channel for each nozzle, which interconnect an ink reservoir in the printhead with the nozzles.
In a typical piezoelectric ink jet printing system, the pressure pulses that eject liquid ink drops are produced by applying an electric pulse to the piezoelectric devices. Each piezoelectric device is individually addressable to enable a firing signal to be generated and delivered to each piezoelectric device. The firing signal causes the piezoelectric device receiving the signal to bend or deform and pressurize a volume of liquid ink in a pressure chamber adjacent the piezoelectric device. As pressure forces a quantity of ink to be displaced from the chamber to eject a drop of ink from the nozzle, commonly called an inkjet or jet, associated with each piezoelectric device. The ejected drops form an image on the image receiving member opposite the printhead. The respective channels from which the ink drops were ejected are refilled by capillary action from an ink supply.
The printing speed and image resolution of an inkjet printer depend, at least in part, on the density of ink ejectors in the printhead. In multi-pass printing, the print speed and image resolution can be traded off against one another to achieve a desired balance between print speed and image quality. The maximum resolution and print speed that a single inkjet printhead generates are determined, at least in part, by the number of inkjet ejectors present in the printhead. A greater inkjet ejector density allows for a printhead with a higher resolution and/or print speed. Being able to accommodate various print resolutions and speeds in the manufacturing of inkjet printing systems is important.